Responding to a forum post on upcoming ARM server offerings, Linus Torvalds makes a compelling case for why Linux and x86 completely overwhelmed commercial Unix and RISC:
Guys, do you really not understand why x86 took over the server market?
It wasn’t just all price. It was literally this “develop at home” issue. Thousands of small companies ended up having random small internal workloads where it was easy to just get a random whitebox PC and run some silly small thing on it yourself. Then as the workload expanded, it became a “real server”. And then once that thing expanded, suddenly it made a whole lot of sense to let somebody else manage the hardware and hosting, and the cloud took over.